Cap cylindrical-ovoid in youth, up to 3.0 cm tall, 1.5 cm wide, becoming obtuse-conic to campanulate, eventually broadly-conic to nearly plane, 2.0-4.0 cm fully expanded; margin decurved at first, slightly wavy, striate to near the disc, soon plicate, in age recurved and torn; surface dull yellowish, mustard-brown, to buff at the disc, paler towards the margin, greyish at maturity; cap surface covered with evanescent, whitish to buff, felty, universal veil fragments, these concentrated at the disc; context thin, approximately 1.0 mm at the disc, colored like the disc; deliquescent; odor and taste not distinctive.
Gills free, crowded, relatively broad, up to 6.0 mm, obtuse at the margin; edges and faces minutely hairy (use hand lens), cream-colored, then greyish, finally blackish from maturing spores; lamellulae three to four-seried.
Stipe 2.0-6.0 cm long, 2.0-7.0 mm thick, equal except enlarged at the base, hollow at maturity, fragile; surface whitish, sparsely pruinose, striate, to glabrous in age; partial veil absent; a thin, white, collar-like volva often found at the base of young specimens.
Spores 11.0-15.5 x 6.5-8.5 µm, smooth, elliptical to almond-shaped in face-view, slightly narrowed in side-view; germ pore eccentric, up to 2.0 microns broad; hilar appendage inconspicuous; spores blackish in deposit.
Solitary, scattered, to gregarious on wood chips, sawdust, and stable straw, but not dung; fruiting after moist periods year-round; common
Coprinellus flocculosus bears a resemblance to Coprinellus micaceus, a familiar and well-known species that grows in clusters, usually at the base of dying trees or rotting stumps. Coprinellus flocculosus differs in its scattered fruitings, usually on sawdust, woodchips, straw etc. It is also has a different type of veil, consisting of felt-like fragments rather than the clumps of globose cells which give rise to the glistening appearance of C. micaceus. Additionally, remnants of the universal veil in Coprinellus flocculosus may form a thin collar at the base of the stipe. Another species similar to Coprinellus flocculosus is Coprinellus domesticus. It differs in having a cap with a more tawny-brown disc, a somewhat granular appearing veil, and a preference for fruiting on hardwood logs and stumps. Microscopically it is distinguished by thick-walled rather than thin-walled velar cells, and smaller spores with a central, not eccentric germ pore.